Nerve axon is known to play an important role in transport of nutritional factor, neurotransmitter, organelle and the like in nerve cell, and axon function disorder, axonal degeneration and intracellular accumulation of axon binding protein tau are observed in various neurodegenerative diseases (Non-Patent Document 1 and Non-Patent Document 2). Diseases characterized by intracellular tau accumulation are collectively called pathologically as tauopathy, and they encompass Alzheimer's disease, progressive supranuclear palsy and the like (Non-Patent Document 3). HDAC6 is an enzyme which plays a role in deacetylation of axon component, tubulin (Non-Patent Document 4), and microtubule containing acetylated tubulin is known to contribute to stability (Non-Patent Document 5). In addition, it is reported that Tubastatin A having a HDAC6 inhibitory activity increases acetylation of tubulin in tauopathy mouse model, and shows therapeutic effectiveness (Non-Patent Document 6). Therefore, the above-mentioned reports suggest that HDAC6 inhibitor has the potential to be a therapeutic drug for Alzheimer's disease and progressive supranuclear palsy via stabilization of axon.
As heterocyclic compounds, for example, the following compound are known.
(1) Patent Document 1 discloses a compound represented by the following formula:
wherein each symbol is as defined in the document, which is a HDAC inhibitor, and is effective for the treatment of autoimmune diseases, inflammatory diseases, metabolic/osteoarticular degenerative diseases, neurodegenerative diseases/central diseases (e.g., schizophrenia, Alzheimer's disease (dementia of Alzheimer type), Parkinson's disease, Huntington's disease, Rubinstein-Taybi syndrome, muscular dystrophy, Rett syndrome, Charcot-Marie-Tooth disease, depression), neoplastic diseases and the like.(2) Patent Document 2 discloses a compound represented by the following formula:
wherein each symbol is as defined in the document, which is a HDAC inhibitor, and is effective for the treatment of autoimmune diseases, inflammatory diseases, metabolic/osteoarticular degenerative diseases, neurodegenerative diseases/central diseases (e.g., schizophrenia, Alzheimer's disease (dementia of Alzheimer type), Parkinson's disease, Huntington's disease, Rubinstein-Taybi syndrome, muscular dystrophy, Rett syndrome, Charcot-Marie-Tooth disease, depression), neoplastic diseases and the like.(3) Patent Document 3 discloses a compound represented by the following formula:
wherein each symbol is as defined in the document, which is a HDAC inhibitor, and is effective for the treatment of autoimmune diseases, inflammatory diseases, metabolic/osteoarticular degenerative diseases, neurodegenerative diseases/central diseases (e.g., schizophrenia, Alzheimer's disease (dementia of Alzheimer type), Parkinson's disease, Huntington's disease, Rubinstein-Taybi syndrome, muscular dystrophy, Rett syndrome, Charcot-Marie-Tooth disease, depression), neoplastic diseases and the like.(4) Patent Document 4 discloses a compound represented by the following formula:
wherein each symbol is as defined in the document, which is a HDAC inhibitor, and is effective for the treatment of autoimmune diseases, inflammatory diseases, metabolic/osteoarticular degenerative diseases, neurodegenerative diseases/central diseases (e.g., schizophrenia, Alzheimer's disease (dementia of Alzheimer type), Parkinson's disease, Huntington's disease, Rubinstein-Taybi syndrome, muscular dystrophy, Rett syndrome, Charcot-Marie-Tooth disease, depression), neoplastic diseases and the like.(5) Patent Document 5 discloses a compound represented by the following formula:
wherein each symbol is as defined in the document, which is a HDAC6 inhibitor, and is effective for the treatment of HDAC6-mediated diseases (e.g., infections, tumor, endocrine/nutritional/metabolic diseases, mental and behavioral disorders, neurological diseases, diseases of the eye and adnexa, cardiovascular diseases, respiratory diseases, digestive diseases, diseases of the skin and subcutaneous tissue, diseases of the musculoskeletal system and connective tissue, or congenital malformations, deformations and chromosomal abnormalities).(6) Patent Document 6 discloses a compound represented by the following formula:
wherein each symbol is as defined in the document, which is a HDAC6 inhibitor, and is effective for the treatment of HDAC6-mediated diseases (e.g., infections, tumor, endocrine/nutritional/metabolic diseases, mental and behavioral disorders, neurological diseases, diseases of the eye and adnexa, cardiovascular diseases, respiratory diseases, digestive diseases, diseases of the skin and subcutaneous tissue, diseases of the musculoskeletal system and connective tissue, or congenital malformations, deformations and chromosomal abnormalities).(7) Patent Document 7 discloses a compound represented by the following formula:
wherein each symbol is as defined in the document, which is a HDAC6 inhibitor, and is effective for the treatment of HDAC6-mediated diseases (e.g., infections, tumor, endocrine/nutritional/metabolic diseases, mental and behavioral disorders, neurological diseases, diseases of the eye and adnexa, cardiovascular diseases, respiratory diseases, digestive diseases, diseases of the skin and subcutaneous tissue, diseases of the musculoskeletal system and connective tissue, or congenital malformations, deformations and chromosomal abnormalities).(8) Patent Document 8 discloses a compound represented by the following formula:
wherein each symbol is as defined in the document, which is a HDAC6 inhibitor, and is effective for the treatment of HDAC6-mediated diseases (e.g., infections, tumor, endocrine/nutritional/metabolic diseases, mental and behavioral disorders, neurological diseases, diseases of the eye and adnexa, cardiovascular diseases, respiratory diseases, digestive diseases, diseases of the skin and subcutaneous tissue, diseases of the musculoskeletal system and connective tissue, or congenital malformations, deformations and chromosomal abnormalities).